Can lid opening tab, can lid, method for manufacturing can lid opening tab

ABSTRACT

A can lid opening tab includes: a pulling-up part provided on one end side in a longitudinal direction; a pressing-down part provided on another end side in the longitudinal direction; a fixing part provided between the pulling-up part and the pressing-down part, and sectioned and formed by a U-shaped slot, and fixed on a can lid body; and the curling part formed continuously on the circumference except for a connecting piece cutting trace provided at the pressing-down part. A step-less unprocessed deflection face with the periphery surrounded without disconnection by the curling part is provided between the fixing part and the pulling-up part, and a display part is provided on at least one face side of the deflection face.

TECHNICAL FIELD

The present invention relates to a can lid opening tab, a can lidincluding the can lid opening tab, and a method for manufacturing a canlid opening tab.

BACKGROUND ART

A can lid including an opening tab of a stay-on type tab is generallyknown. Such a can lid is configured such that a tab is fixed at thepanel of a can lid body. The tab includes a fixing part to be fixed tothe can lid body by a rivet, a pulling-up part separated from the fixingpart by a slit, and to be pulled up by fingers, and a pressing-down partto be pressed down in response to pulling up of the pulling-up part withthe fixing part as a fulcrum. For such a can lid including the tab, thepressing-down part of the tab ruptures the score formed at the panel ofthe can lid body, so that the opening piece sectioned by the score isretracted into the inside of the can, thereby opening the can lid.

Such an opening tab in the can lid reduces the force to be applied onthe fingers for the opening operation using the principle of the leverwith the fixing part as the fulcrum, the pulling-up part as the point ofeffort, and the pressing-down part as the point of load. The length fromthe fixing part to the pulling-up part is longer than the length fromthe fixing part to the pressing-down part.

For such an opening tab, display information such as a two-dimensionalcode is provided at the portion from the fixing part to the pulling-uppart formed relatively long. At this step, when the display informationis provided on the back face side of the tab facing the can lid body, itis configured such that the display information is hidden until the canlid is opened, and only the purchaser of a can product can access thedisplay information by pulling up the pulling-up part of the tab foropening the can lid (refer to PTL 1).

CITATION LIST Patent Literature

-   [PTL 1] Japanese Patent Application Publication No. 2019-104531

SUMMARY OF INVENTION Technical Problem

The can lid opening tab is required to be ensured in rigidity along thelongitudinal direction so that the pressing-down part is pressed downwith reliability in synchronization with pulling up of the pulling-uppart. To this end, a curling part is formed at a periphery of the tab,and reinforcing concavo-convex processing is performed between thepulling-up part and the fixing part.

At this step, when downward convex processing is tried to be performed,the convex processing causes the back face of the tab to approach thesurface of the lid main body. For this reason, in order to avoid thecontact of the back face of the tab with the surface of the lid mainbody, the precision of processing is required to be adjusted exactly,undesirably resulting in a complicated production process.

Further, in the case where reinforcing concavo-convex processing isperformed on between the pulling-up part and the fixing part, when themarking position of the display information is deviated from the centralposition, or information is marked widely inside the curling part, apart of the display information may lie on the step portion resultingfrom concavo-convex processing. Thus, the step causes distortion in thedisplay, undesirably making it impossible to obtain favorable visibilityof the display information.

It is an object of the present invention to cope with such a problem.Namely, it is an object of the present invention to eliminate thenecessity of reinforcing concavo-convex processing requiring an exactprocessing precision while ensuring the rigidity in the longitudinaldirection of the tab itself, thereby simplifying the production process;to enable ensuring of the favorable display visibility even whenmisplacement of display is caused, or display is performed widely insidethe curling part, or the like.

Solution to Problem

In order to solve such problems, the present invention includes thefollowing configuration.

A can lid opening tab, includes: a pulling-up part provided on one endside in a longitudinal direction; a pressing-down part provided onanother end side in the longitudinal direction; a fixing part providedbetween the pulling-up part and the pressing-down part, and sectionedand formed by a U-shaped slot, and to be fixed on a can lid body; and acurling part formed continuously on a circumference except for aconnecting piece cutting trace provided at the pressing-down part. Thecan lid opening tab is characterized in that a step-less unprocesseddeflection face with a periphery surrounded without disconnection by thecurling part is provided between the fixing part and the pulling-uppart, and a display part is provided on at least one face side of thedeflection face.

Advantageous Effects of Invention

With the can lid opening tab having such features, it is possible toeliminate the necessity of reinforcing concavo-convex processingrequiring adjustment of an exact processing precision while ensuringrigidity in the longitudinal direction of the tab itself. This cansimplify the production process. Further, with the can lid opening tabhaving such features, it is possible to ensure favorable displayvisibility even when misplacement of display is caused, or display isperformed widely inside the curling part.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an explanatory view showing a can lid opening tab inaccordance with an embodiment of the present invention (FIG. 1 at (a) isan A-Across sectional view, FIG. 1 at (b) is a plan view, and FIG. 1 at(c) is a back view)).

FIG. 2 is an explanatory view showing a method for manufacturing the canlid opening tab in accordance with the embodiment of the presentinvention, and a can lid on which the can lid opening tab is mounted.

FIG. 3 is an explanatory view in a back view showing a forming processof the can lid opening tab (FIG. 3 at (a) a state after marking of adisplay part, FIG. 3 at (b) a state after hole processing, and FIG. 3 at(c) a state after stamping of a periphery).

FIG. 4 is an explanatory view in a back view showing a forming processof a can lid opening tab (FIG. 4 at (a) a state after processing of theinside of the periphery, and shaping processing of a fixing part, FIG. 4at (b) a state after a bend process of the periphery, and FIG. 4 at (c)a state after a curl process of the periphery).

FIG. 5 is an explanatory view showing movement of a processing tool ofthe curl process (FIG. 5 at (a) before the process, and FIG. 5 at (b)after the process).

FIG. 6 is an explanatory view showing another example of the processingtool of the curl process.

FIG. 7 is an explanatory view of an example (FIG. 7 at (a) is a planview, and FIG. 7 at (b) is a B-B cross sectional view).

FIG. 8 is an explanatory view of an example (an A-A cross sectional viewin FIG. 7 at (a)).

DESCRIPTION OF EMBODIMENTS

Below, referring to the accompanying drawings, embodiments of thepresent invention will be described. In the following description, thesame reference numerals and signs indicate portions having the samefunction, and repetitive description referring to the drawings will beappropriately omitted. The arrow X direction in FIG. 1 shows alongitudinal direction of a can lid opening tab, the arrow Y directionshows a direction (width direction) orthogonal to the X direction in aplan view, and the arrow Z direction shows a thickness direction of thecan lid opening tab.

As shown in FIG. 1 , the can lid opening tab (below, tab) 1 is providedwith a pulling-up part 2 on one end side in the longitudinal direction(the X direction shown), a pressing-down part 3 on the other end side inthe longitudinal direction (the X direction shown), and a fixing part 4between the pulling-up part 2 and the pressing-down part 3.

The pulling-up part 2 is a portion on which fingers of a personperforming an opening operation are put, and is pulled up in the Zdirection shown, thereby performing the opening operation. Thepressing-down part 3 is a portion to be pressed down in the oppositedirection by pulling up of the pulling-up part 2. This portion comes incontact with a panel of a can lid body, and is pressed down, resultingin rupture of a score of the can lid body.

The fixing part 4 is sectioned and formed by a U-shaped slot 5, andincludes a rivet hole 6 into which a rivet to be provided on the panelof the can lid body is inserted. The rivet to be provided on the panelof the can lid body is inserted into the rivet hole 6, and is crimped,so that the fixing part 4 is fixed to the can lid body.

At the center of the pressing-down part 3, there is a connecting piececutting trace 7. Then, a curling part 8 is formed at a circumferenceedge of the tab 1 except for the connecting piece cutting trace 7. Thecurling part 8 enhances bending rigidity along the longitudinaldirection of the tab 1 in order for the tab 1 to function as a leverwith the pulling-up part 2 as the point of effort, the fixing part 4 asthe fulcrum, and the pressing-down part 3 as the point of load.

At this step, at a position at which the connecting piece cutting trace7 is present, disconnection cannot avoid being caused in the curlingpart 8. However, the provision of the connecting piece cutting trace 7in the pressing-down part 3 can set the disconnected part of the curlingpart 8 at the position not to be applied with a bending force when thepulling-up part 2 is pulled up for the opening operation.

The tab 1 is provided with a shaping part 10 convex opposite to the Zdirection at a periphery of the fixing part 4. Then, a step-lessunprocessed deflection face 20 is formed at a portion between the fixingpart 4 and the pulling-up part 2, a portion outside the shaping part 10.The deflection face 20 is not subjected to concavo-convex processing bya processing tool at the portion itself, and a downwardly convexdeflection face 20 is formed when the curling part 8 at the peripherythereof is formed.

The back face 21 facing the can lid body of the deflection face 20 isprovided with a display part P. The back face 21 provided with thedisplay part P is surrounded without disconnection at the peripherythereof by the curling part 8, and an uniform face without a step isformed inside the curling part 8 and outside the shaping part 10. Forthis reason, the display part P will not be deteriorated in visibilitydue to a concavo-convex step even when a marking position is a littledeviated from the center, and will not be deteriorated in visibilityeven when the display part P is provided widely inside the curling part8. Incidentally, herein, the example is shown in which the display partP is provided on the back face 21 of the deflection face 20. However,the display part P may be provided on the front face side of thedeflection face 20, and may be provided on both the front and back facesthereof.

Further, the deflection face 20 enhances the bending rigidity in thelongitudinal direction of the tab 1 by deflection of itself. For thisreason, even when the portion between the fixing part 4 and thepulling-up part 2 is not subjected to concavo-convex processing by aprocessing tool, the tab 1 has bending rigidity enough to function as alever with the puffing-up part 2 as the point of effort, the fixing part4 as the fulcrum, and the pressing-down part 3 as the point of load.

The deflection face 20 of the tab 1 has a smooth deflection shape inwhich the amount of deflection is maximum at a point closer to thefixing part 4 side than to the center from the circumference in thedeflection along the X direction (longitudinal direction) of FIG. 1 .The maximum amount of deflection at the deflection face 20 is preferably0.2 mm or more. By assuming a smooth deflection shape in which theposition of the maximum amount of deflection of the deflection face 20is set closer to the fixing part 4, the cross-sectional two-dimensionalmoment is increased, which enables an increase in rigidity of the tab 1.Further, by setting the position of the maximum deflection of deflectionalong the X direction closer to the fixing part 4, it is possible tosufficiently ensure the gap for fingers to be put under the pulling-uppart 2 for opening upon mounting the tab 1 at the can lid.

The display part P is a drawing part drawn by, for example, lasermarking or ink jet printing, on which a two-dimensional code, alogotype, a picture, a letter, a number, or the like is drawn. Afterdrawing of the display part P, a processing tool will not impinge on thedisplay part P. For this reason, the shape of the tab 1 will not disturbthe visibility of the display part P. Incidentally, when the displaypart P is formed by laser marking, a colored painted surface is formedon the surface of the tab 1.

The tab 1 and the can lid to which it is mounted are manufactured asshown in FIG. 2 . Namely, a tab material T rewound from a coil C is,first, passed through a drawing device (e.g., a laser marker) 30, sothat the display part P drawn by laser marking or the like is formed onthe back face of the tab material T. Then, the tab material T includingthe display part P formed thereon is passed through a tab shapingmachine 31, resulting in the formation of the tab 1.

FIGS. 3 and 4 each show the tab forming process during which the tabmaterial T passes through between the drawing device 30 and the tabshaping machine 31. FIG. 3 at (a) shows a state in which the displaypart P is drawn on one face side (back face side) of the long tabmaterial T. The display part P is formed in the drawing device 30 shownin FIG. 2 . FIG. 3 at (b) shows a state in which the tab material T issubjected to hole processing in the tab shaping machine 31. Herein, apair of holes T1 and T2 for forming a connecting piece (carry point) T3extending in the longitudinal direction are formed at a position awayfrom the display part P in the longitudinal direction of the tabmaterial T, and the U-shaped slot 5 and the rivet hole 6 for sectioningand forming the fixing part 4 are formed between the display part P andthe connecting piece T3. In FIG. 3 at (c), a cut line T4 for connectingthe pair of holes T1 and T2, and defining the further outer side of thecircumference edge of the tab is formed by stamping.

FIG. 4 at (a) shows a state in which the inside of the cut line T4 isprocessed, and the shaping part 10 is formed near the rivet hole 6 andthe slot 5. FIG. 4 at (b) shows a state after bend processing the insideof the cut line T4 along the circumference shape of the tab 1. FIG. 4 at(c) shows a state in which a bent piece T5 formed by bend processing iscurl processed, thereby forming the curling part 8.

In curling of curl processing the bent piece T5 formed by bend process,and forming the curling part 8 at the periphery of the tab except forthe connecting piece T3, as shown in FIG. 5 , a lower tool 12 having adie part 12A for subjecting the bent piece T5 to curl shaping, and anupper tool 11 for pressing the tab material T against the lower tool 12are used. As shown in FIG. 5 at (a), the tab material T subjected tobend processing is arranged between the upper tool 11 and the lower tool12. As shown in FIG. 5 at (b), the upper tool 11 and the lower tool 12are made closer to each other, so that the bent piece T5 of the tabmaterial T is pressed against the die part 12A of the lower tool 12,resulting in the formation of the curling part 8.

At this step, the lower tool 12 has an opening part 12B for making thedisplay part P unprocessed. The opening part 12B is provided inside thedie part 12A. The positioning of the display part P inside the openingpart 12B prevents a processing tool (the upper tool 11 and the lowertool 12) from impinging on the portion at which the display part P isformed. Then, the provision of the opening part 12B at the lower tool 12results in the formation of the downwardly convex deflection face 20 atthe portion including the display part P provided thereon when thecurling part 8 is formed.

The opening part 12B may be set in an opened state as shown in FIG. 5 ,or may be provided with a movable support member 12C as shown in FIG. 6. The movable support member 12C descends according to the curvedeformation of the tab material T including the display part P formedthereon when the deflection face 20 is formed in the opening part 12B.The movable support member 12C supports the deflection face 20 from theback face side, thereby performing control so as to prevent thedeformation of the deflection face 20 from being excessively caused.

The movable support member 12C is supported by, for example, a spring,and is movable with the formation of the deflection face 20. For thisreason, even when the display part P impinges on the movable supportmember 12C, the display will not be broken. Further, the movable supportmember 12C may include an elastic member such as rubber or resin.

The tab material T which has passed through a tab shaping machine 31 isfed with the tab 1 connected to the tab material T by the connectingpiece T3 as shown in FIG. 4 at (c), to a conversion press 32 shown inFIG. 2 . With the conversion press 32, shaping of the can lid body isperformed, and the rivet hole 6 of the tab 1 is positioned with respectto the rivet position of the can lid body. Then, the connecting piece T3is cut, and the tab 1 is separated from the tab material T, and therivet is inserted into the rivet hole 6, and is crimped. Thus, the tab 1is mounted on the can lid body. This results in a can lid W includingthe tab 1, and the can lid body to which the fixing part 4 of the tab 1is fixed, and which has a score to be ruptured by pressing down of thepressing-down part 3.

Thus, the tab 1 in accordance with the embodiment of the presentinvention is configured as follows: the display part P is formed on theback face 21 facing the can lid body, so that display information ishidden until the can lid is opened, and only a purchaser of a canproduct can access the display information by pulling up the pulling-uppart 2 of the tab 1 for opening the can lid. As a result of this, it ispossible to use the display part P as a prize, a lot, or the like. Then,in that case, the curling part 8 without disconnection is formed at theperiphery of the display part P. In addition, the display part P isprovided on the back face 21 of the unprocessed deflection face 20. As aresult, sufficient bending rigidity along the longitudinal direction ofthe tab 1 is ensured.

Then, the back face 21 of the deflection face 20 on which the displaypart P is formed is made unprocessed. This eliminates the necessity ofthe adjustment of the exact processing precision, which can simplify theproduction process. Further, there is no step resulting fromconcavo-convex processing on the deflection face 20 on which the displaypart P is formed. For this reason, it is possible to ensure favorabledisplay visibility even when misplacement of display is caused, ordisplay is performed widely inside the curling part 8.

EXAMPLE

As shown in FIG. 7 , for each tab 1 (each of samples 1 to 5) having thedeflection face 20 with an X direction width m=10 mm, and a Y directionwidth n=14.4 mm, the amounts of deflection relative to the circumferencewere measured at seven sites of (1) to (7) of FIG. 7 at (b) along the Ydirection, in cross section (B-B cross section) at the position closerto the fixing part 4 from the center at an X direction width m, namely,the position resulting in (mt/m)>½. Of the (1) to (7), (1) and (7) arethe points on the circumference, and (2) to (6) are the pointssectioning the Y direction width n at equal intervals. The site of (4)is the vicinity of the center in the Y direction of the deflection face20.

Further, at respective points of (8), (9), (10), (4), (11), and (12) ofFIG. 8 along the X direction ((4) is the same as the position in FIG. 7at (b)) in the cross section (A-A cross section) of the center in the Ydirection width n, the amounts of deflection with respect to thecircumference were measured.

The measurement value of the amount of deflection at each site in eachsample, the measurement values of the tab breaking strength (N) and thetab breaking angle (deg) in each sample, the tab breaking strengthevaluation, the tab breaking angle evaluation, the visibilityevaluation, and the comprehensive evaluation are shown in Table 1.

The tab breaking strength herein denotes the force applied on thepulling-up part 2 immediately before breaking of the tab 1 upon mountingthe tab 1 on the lid without a score, and raising the tab 1. The tabbreaking angle denotes the angle formed between the tab 1 and the lid atthe time of occurrence of tab breaking upon mounting the tab 1 on thelid without a score, and raising the tab 1. Each sample includes fiveindividuals similarly shaped, and the numerical value of the table isthe average value of the measurement values for each of the fiveindividuals.

TABLE 1 Sample 5 Sample 4 Sample 3 Sample 2 Sample 1 Measurement site0.00 0.00 0.00 0.00 0.00 (1) Amount of deflection 0.10 0.12 0.16 0.170.36 (2) [mm] 0.16 0.21 0.22 0.28 0.58 (3) 0.19 0.22 0.25 0.31 0.67 (4)0.16 0.20 0.21 0.28 0.59 (5) 0.08 0.12 0.16 0.18 0.37 (0) 0.00 0.00 0.000.00 0.00 (7) 0.11 0.11 0.12 0.16 0.20 (8) 0.14 0.14 0.20 0.24 0.29 (9)0.16 0.16 0.24 0.28 0.38 (10)  0.16 0.16 0.23 0.27 0.36 (11)  0.13 0.140.16 0.18 0.24 (12)  30.62 30.88 31.78 31.94 31.10 Tab breaking strength[N] 69.84 72.96 78.04 85.44 70.84 Tab breaking angle [deg] BB BB AA AAAA Tab breaking strength evaluation CC BB BB AA BB Tab breaking angleevaluation AA AA AA AA BB Visibility evaluation CC BB BB AA BBComprehensive evaluation

Herein, the evaluation of the tab breaking strength is conducted asfollows: 30 N or more is rated as BB, and 31 N or more is rated as AA.The evaluation of the tab breaking angle is conducted as follows: lessthan 70° is rated as CC, 70° or more is rated as BB, and 80° or more israted as AA.

Further, as the visibility evaluation, whether the distortion of thepattern (or the code) on the deflection face 20 of the tab 1 hasoccurred, or not is evaluated. The one which has not undergone theoccurrence of distortion is rated as AA, and the one which has hardlyundergone the occurrence of distortion is rated as BB.

In the Example, by setting the maximum amount of deflection (the amountof deflection of the measurement site (4)) of the deflection face 20 inthe tab 1 at 0.2 mm or more, favorable evaluations are obtained in termsof both aspects of the tab breaking strength and the tab breaking angle.In consideration of the visibility evaluation, even when the maximumamount of deflection is larger than 0.4 mm (0.67 mm), the visibility canbe ensured. However, when the maximum amount of deflection is set at 0.4mm (0.31 mm) or less, the visibility is further improved. Therefore, inthe comprehensive evaluation, it could be confirmed that the sample 2 isparticularly good, and, when importance is placed on the visibility, thesamples 2, 3, and 4 are particularly good.

Up to this point, the embodiments of the present invention have beendescribed in details by reference to the accompanying drawings. However,the specific configuration is not limited to the embodiments, and thepresent invention includes even the changes of the design within thescope not departing from the gist of the present invention, or the like.Further, the respective embodiments can be combined by using mutualtechnologies so long as there is no particular contradiction or problemin the object and configuration thereof, and the like.

REFERENCE SIGNS LIST

-   1 Can lid opening tab (tab)-   2 Pulling-up part-   3 Pressing-down part-   4 Fixing part-   5 Slot-   6 Rivet hole-   7 Connecting piece cutting trace-   8 Curling part-   10 Shaping part-   11 Upper tool-   12 Lower tool-   20 Deflection face-   21 Back face-   30 Drawing device-   31 Tab shaping machine-   32 Conversion press-   T Tab material-   P Display part-   T1, T2 Hole-   T3 Connecting piece-   T4 Cut line-   T5 Bent piece-   W Can lid

1. A can lid opening tab, comprising: a pulling-up part provided on oneend side in a longitudinal direction; a pressing-down part provided onanother end side in the longitudinal direction; a fixing part providedbetween the pulling-up part and the pressing-down part, sectioned andformed by a U-shaped slot, and to be fixed on a can lid body; and acurling part formed continuously on a circumference except for aconnecting piece cutting trace provided at the pressing-down part,wherein a step-less unprocessed deflection face with a peripherysurrounded without disconnection by the curling part is provided betweenthe fixing part and the pulling-up part, and a display part is providedon at least one face side of the deflection face.
 2. The can lid openingtab according to claim 1, wherein the display part is a drawing partdrawn by laser marking or ink jet printing.
 3. The can lid opening tabaccording to claim 1, wherein the deflection face has a smoothdeflection shape such that an amount of deflection is maximized at aposition closer to a fixing part side than to a center from acircumference.
 4. The can lid opening tab according to claim 1, whereinmaximum amount of deflection in the deflection face is 0.2 mm or more.5. A can lid, comprising: the can lid opening tab according to claim 1;and a can lid body to which the fixing part is fixed, and which has ascore to be ruptured by pressing down of the pressing-down part.
 6. Amethod for manufacturing a can lid opening tab, including: displaying ofdrawing a display part on at least one face side of a long tab material;forming a pair of hole parts for forming a connecting piece extending ina longitudinal direction of the tab material at positions separated inthe longitudinal direction from the display part, forming a U-shapedslot for sectioning and forming a fixing part between the display partand the connecting piece, and forming a cut line for connecting the pairof holes and defining an outside of a circumference edge; bendprocessing an inside of the cut line along a circumference shape of atab; and curling of curl processing a bent piece formed by the bendprocessing, and forming a curling part at a periphery of the tab exceptfor the connecting piece, wherein for the curling, a lower tool having adie part for subjecting the bent piece to curl shaping, and an uppertool for pressing the tab material against the lower toll are used, andthe lower tool has an opening part for making the display partunprocessed.
 7. The method for manufacturing a can lid opening tabaccording to claim 6, wherein the opening part is provided with amovable support member descending according to curve deformation of thetab material including the display part formed thereon.
 8. The can lidopening tab according to claim 3, wherein maximum amount of deflectionin the deflection face is 0.2 mm or more.